Right-click the file and select "7-Zip" > "Extract here" or "Extract to...". Mac/Linux: Use software like p7zip .
If the file is a "solid" archive, you might be able to replace broken segments if you have a non-corrupt version of the file. FestivalPatronageHauntUnfixable.7z
A container for a complex creative work. Right-click the file and select "7-Zip" > "Extract